Unless my eyes deceive me, what’s with the white plume of smoke in the distance? That’s opposite-direction from the primary bomb; as opposed to the ‘second’ explosion. And, it’s present as the primary blast goes off.

@Skydrifter – It’s just a change in perspective that you’re not used to. They’ve been showing a lot of pics from the finish line looking up the street. This is much further up the street looking toward the finish line. You can see the finish line bomb had already gone off (hence the smoke) and the photo is taken of the second bomb just as it’s going off.

I was a marathon runner on Monday in Boston so I can fully explain what this photo is… the explosion you are seeing right in front there is the SECOND bomb… the white plume of smoke further down Boylston Street was the first bomb which had gone off just five seconds earlier. My wife and I were running together and were about 50 yards from the Finish Line when the first bomb went off to the left of us. We were uninjured – exited at Exeter Street – did not finish the marathon – but are alive. Prayers for all the injured, the 3 dead innocent people and their families. RJ

If you mean photo 1 of 32, that’s an image of the second blast, which took place anywhere between 10-20 seconds after the first. This image is looking east-northeast along Boylston street; the 2nd bomb was west of the first one. I know this because my home is just out of frame to the right of this photo.

The other photos you’ve seen have been taken from the perspective of the finish line, looking toward the runners’ faces approaching the line. Here, the photographer is positioned further back, looking toward the finish line, with photo of the backs of runners who are running toward the finish line. So, the large explosion above is the 2nd bomb site. The plume of white smoke in the distance is the 1st bomb site — closer to the finish line.